Em Qui, 2008-07-17 às 11:47 +0200, Kunzler, Andreas escreveu: > Dear List, > > I ran into some trouble by calculating differences. For me it is > important that differences are either 0 or not. > > So I don't understand the outcome of this calculation > > 865.56-(782.86+0+63.85+18.85+0) > [1] -1.136868e-13 > > I run R version 2.71 on WinXP
Hi Andreas Kunzler, Your problem is cause by numeric represntation in computer (Floating-Point numbers) and this topic is explain in R FAQ 7.31 But the solution for your calculations is possible using the "guard digits" approach, so if you needd solve: 865.56-(782.86+0+63.85+18.85+0) Using 865.56/100 -(782.86+0+63.85+18.85+0)/100 More details in http://docs.sun.com/source/806-3568/ncg_goldberg.html (This links is indicated in R FAQ 7.31) -- Bernardo Rangel Tura, M.D,MPH,Ph.D National Institute of Cardiology Brazil ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.